SIM only deals: the best plans in December 2017

We dig out the best SIM only deals so you don't have to. Whether you need an unlimited data plan, a temporary 30 day SIM or simply want a cheap SIM only deal, you've come to the right place.

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So you've come to the end of your phone contract? You basically have two options - grab a brand new mobile phone deal on one of the latest and greatest smartphones on the market. Or keep your beloved phone of the last two years and sign up for one of the cheap SIM only deals on this page.

A SIM only deal is a mobile phone plan that offers calls, texts and data in return for a monthly fee, but does not come bundled with a phone. Leaving the phone out of the equation gives you more flexibility (especially if you go for a 30-day rolling contract) or is ideal if you're eyeing up a new SIM-free phone.

And if you're still unsure whether SIM-only is the route for you, our expert advice will help you decide - our all knowing FAQ includes tips on switching your number, the networks that offer free gifts and answers to a host of other questions.

The best SIM only deals of the week are:

We've run the figures and plucked out the very best sim only deals available this month. Whether you’re after the cheapest plan possible, want to dig out the best value big data SIM plan or just want an all-round great deal but don’t know how much to spend, you’ll find a recommendation just for you.

1. The absolute cheapest SIM only deal out there

iD Mobile | 1 month contract | 500MB data | 500 minutes | 5000 texts | £3.99 per monthThis is the cheapest readily available SIM only deal currently available in the UK. If you just need to keep a phone up and running for occasional use, this is the least you can pay. You'd be advised to either keep mobile data switched off or be careful what apps are updating in the background. BUT WAIT, CHECK OUT THE NEXT DEAL FIRST!

2. The best 1GB+ SIM only deal

iD mobile | £5 month contract | 2.25GB data | 250 minutes | 5000 texts | £5 per monthFor a limited time iD has majorly improved its £5 tariff. If you're looking for a super cheap SIM only deal but don't want to limit yourself too much with data, 2.25GB for £5 is the best option out there right now - but it will disappear as 2017 comes to a close. A few pounds more a month gets you way more data, so you keep scrolling down if you're worried that 2.25GB won't be enough.

3. The best 2GB-4GB SIM only deal

Three | 12 month contract | 4GB data | Unlimited minutes and texts | £10 per monthLeading the way when it comes to what the major networks can offer, Three SIM only deals are extremely attractive. If you're prone to viewing a few YouTube videos and streaming some Spotify songs away from Wi-Fi, this 4GB option may suit you better than ID's SIMs above.

5. The best 10GB-16GB SIM only deal

Three | 12-month contract | 12GB data | Unlimited calls and texts | £13 per monthThis Three tariff is by far the the most popular on the market at the moment (even though it has just gone up by a pound a month). £13 for a very healthy 12GB of data is superb value. This deal hits the sweet spot between plenty of data and cheap monthly bills - and we love it!

6. The best 20GB-30GB SIM only deal

O2 | 12-month contract | 20GB data | Unlimited mins and texts | £21 per monthIf you want a break from Three's dominance or have loyalty to O2, then this isn't a bad tariff for 20GB of data. Plus, its Priority rewards give you cheap lunches and first dibs on gig tickets. Just make sure you check out the best of the other networks first.

7. The best SIM only deal for unlimited data

Three | 12-month contract | Unlimited data | Unlimited texts | 200 minutes | £22 per monthSometimes, you've just gotta have all the data. This all-you-can-eat data bundle is ideal for the serious mobile user who never needs to worry about poxy thing like data allowances or Wi-Fi. Plus you'll get £35 cashback. Giffgaff can do unlimited for only £20 a month, but once you've used 9GB of data each month, it cuts your speeds down from 4G.

8. Best EE SIM only deal

12-month contract | 2GB data | 1000 minutes | Unlimited texts | £9.75 per month (after cashback)If you've ever gone looking for your new SIM card directly from EE itself, you've probably left the shop laughing with some of the prices it charges. But other retailers sometimes manage to stock them cheaper - handy if you're wedded to the UK's fastest 4G network. This is the cheapest EE SIM around thanks to £98 of cashback, but you do have to remember to claim it in five chunks over the year.

9. Best Three SIM only deal

12-month contract | 30GB data | Unlimited minutes and texts | £18 per monthThree is often the go-to network for big data deals and its exceptional 30GB data deal won the Best Phone Deal award at the Mobile Choice Consumer Awards 2017. And the news keeps getting better - the 600 minutes of calls cap has been removed. A ridiculous bargain!

10. Best data only SIM deal

Three | 12-month contract | 5GB data | £11 per monthIf you use your tablet as a kind of portable TV for catching up with Netflix, iPlayer and Amazon Video while out and about, then this Three data only deal could be a suitable option. You get 5GB for £11 a month. More than a normal SIM, but the best value we can find for using data on an iPad or other tablet.

Should I go SIM only?

If you a) want to save some money; b) don't want to be tied into a lengthy contract; or c) both of the above, then SIM only is well worth considering. In fact, you're probably one of two people if your thoughts are indeed turning to SIM only:

You're coming to the end of your contract and your network is calling you a million times a day to get you to upgrade. Well if your phone is dying a death or you just fancy a change, head to our best mobile phones deal page to see what bargains are lurking, but otherwise going SIM only on your current phone is a no-brainer. You'll wind up paying much less than you are under contract, and you can stick to a rolling 30 day contract so that if your circumstances change, you can get out of the arrangement tout suite.

It's time for a shiny new smartphone and you want to get the best value humanly possible. You'll have to find a few hundred quid up front for the handset (be sure to check our SIM free comparison chart) but box clever and you'll end up paying less over the next 24 months (see below). Plus, if you're a commitment-phobe, most SIM-only plans don't require you to sign up for two years like you would with a normal contract.

Is SIM only cheaper than contract?

It can be. Teaming a SIM only plan with a standalone SIM-free handset could save you a few quid. It's usually the case when a flagship phone hits the market and contracts are made deliberately expensive. Take the Samsung Galaxy S8 as a prime example, where you could have saved over £100 over two years by splashing the £800-odd for the handset and slipping in a cheap SIM card.

Not all the savings you can make are as extravagant, and on big data it's frequently more cost effective to dive into a contract instead. But if you can afford to splash a few hundred pounds up front then the savings over the next couple of years could well be worth it.

Is my phone unlocked - can I use a new SIM in it?

The times have passed since most phones were locked to a network and you had to pay a dodgy backstreet 'engineer' to unlock it. Nowadays, it's standard practice for networks to let you use whatever SIM you want in the phone as soon as you've paid up the original contract (or earlier if you pay them a fee) - and Three ships all its handsets unlocked from the outset.

The exception, alas, is Apple iPhones. They're generally sold locked to the original network that you purchase them with for the life of the handset. Very frustrating if you're looking for a tasty SIM only deal once your 24 month sentence is up.

The good news is that your iPhone (or any other mobile before the end of your contract) can be unlocked - the bad news is that most networks make you pay for the privilege. Insert a friend or family member's SIM into your phone to see whether it's already unlocked and, if it isn't, look for your network below to see how to cut ties with them:

EE Once six months have gone by on your contract, you can call EE on 0800 956 6000 and pay them £8.99 to unlock your phone. It says it will take around 10 days to complete. PAYG phones can be unlocked for free.

O2 As long as you don't own a Samsung Galaxy S8 or S8 Plus (they can't be unlocked until you've paid off your contract), you can unlock any O2 phone - including iPhones - for free if you're on a pay monthly contract. PAYG customers have to pay £15.

Three Fear not, all phones on Three are unlocked as standard. Shove whatever SIM you like in there, it will work a treat.

Vodafone The red network doesn't quite get the same marks as Three, as your phone will be locked to them on arrival. But they have made unlocking handsets absolutely free within 10 days of your request.

What SIM card size do I need?

There are three sizes of SIM card that you can get for your phone, and the one you need will depend on your handset. It's been a while since the traditional, so-called standard SIM (15x25mm) has genuinely been the staple in new phones. Instead, any phone you've bought within the last five or so years is much more likely to require a micro (12x15mm) or nano (8.8x12.3mm) SIM - the iPhone 5 was Apple's first mobile with a nano SIM, while Samsung began using the smallest size in its Galaxy S6.

Before you purchase your new SIM, double-check the manufacturer's website to see what size you require. And if you're simply not sure, most networks now simply send out a triple SIM, so you'll get one of each size.

How do I keep my old number?

Ever heard of PAC codes and wondered what a classic 80s arcade game had to do with telephone numbers? It actually stands for Porting Authorisation Code, and it's the set of digits that you need to grab from your old network to let you transfer over your existing mobile number. If you're on one of the major networks, you can see what phone number you can contact them on here:

EE 07953 966 250

O2 0344 8090202

Vodafone 03333 040 191

Three 0333 300 3333

ID 0333 003 7777

GiffGaff 43431 from your handset

Virgin 0345 6000 789

BT 0800 800 150

Tesco 0345 301 4455

Sky 03300 412 524

Asda 0800 079 2732

If you want to grab a bargain SIM only plan above, but it's on your existing network then your network won't release a PAC code and you'll be forced to take a new phone number.

At least you would have, if it wasn't for this clever (if convoluted) work-around. You have to order a free pay-as-you-go SIM from another network. Once you have it, you can tell your old network that you're moving and they'll give you that precious PAC code. Then, once your number is registered to the substitute network, simply get another PAC code from them. Take that to your old network, and they'll move your number to your new contract. Simple - kind of!

What contract length should I get?

Unlike with a contract, there's a lot more flexibility available when it comes to how long your SIM only plan will last. Two year commitments are virtually unheard of, with the norm being either one year or rolling one month contracts for ultimate flexibility. You can often get better prices if you tie yourself in for 12 months, especially on larger data tariffs. But sticking to one month at a time means that you can effectively hand pick a new plan to suit you every 30 days or so.

How much data do I need?

Because you can change your plan up more regularly than a normal, lengthier contract, it's less crucial to get this nailed from the start. But if you're thinking of grabbing a 12-monther or just put a personal pride on getting things right first time, then we'll help you pick out the sweet spot of data for you.

Firstly, check your phone to see how much data you've been using to date, and whether you have the tendency to use more than your current allowance every month. Then, if you're still unsure, check out our guidance:

0-1GB Tiny amounts of data on SIM only deals could be a blessing or a curse. If you're putting it in a rarely used phone that will scarcely be away from wi-fi then you're quids in. But if you end up with one because your head's turned by the incredible price, then you could end up paying more if you continually go over your allowance.

2-3GB For anybody who needs data for little more than the occasional Google Maps route planning, 2GB and 3GB plans come cheap and give you much more freedom to check the football scores and scroll Facebook away from the wi-fi without danger.

4-8GB If you can't leave the house without having a music streaming service like Spotify pouring into your ears, then it might be worth paying for some extra GBs of data.

10-16GB This is a significant amount of data and some networks offer it for a very appetising price. Whether streaming music, downloading podcasts, watching social media videos, or all three is your thing - you should be covered.

20-30GB Only smartphone junkies that need regular (and hefty) data fixes need bother with this avalanche of GBs. You'll be able to rinse Netflix, Spotify and online games without too much fear of topping out.

Unlimited Maybe it's because you use remarkable amounts of data. Maybe it's because you simply don't want to keep checking how much data you've used every month. Whatever your reason to go unlimited, you have only two choices when it comes to network: Three or GiffGaff.

Do I need unlimited calls and texts?

Call it practicality, call it greediness, call it what you want - it's human nature to want 'unlimited' anything if offered. But you should think genuinely about whether you really need it in a world where the likes of WhatsApp and Skype let you call and text for free over wi-fi or 4G. If you decide that a few thousand monthly minutes and texts should do you, then you could shave off some cash from your bill.

What's the best mobile network for SIM only?

While EE, O2, Vodafone and Three are generally considered the major four networks for contract plans, when it comes to SIM only there are some other key players are well worth a look. See what we think of them below, and whether you'll get any free perks to help persuade you to sign up. Plus, we'll tell you about a couple of other SIM sellers that might be able to wrangle you an even better deal.

EE SIM only deals

If you want fast and furious 4G, then your choice has to be an EE SIM only deal. Its speeds are around 50% faster than the other major networks, which is really noticeable if you like watching films or football on the move. And EE gives you three free months of BT Sport, as well as six months of Apple Music.

O2 SIM only deals

O2's best claim for your contract is with its Priority rewards - from cheap lunch deals and pre-order privileges on gig tickets, to ad-hoc discounts and competitions. Plus, they have 1000s of Wi-Fi hotspots in shops and cafes that you can connect to for free and save your precious data.

Vodafone SIM only deals

Vodafone seems to have been around since mobile phones were cumbersome bricks, but they remain a major player. Look out for a Red Entertainment tariff, which gives you your choice of a NOW TV Entertainment Pass, Spotify Premium or Sky Sports Mobile subscription.

Three SIM only deals

Three is still the only network to offer unlimited data and it often features unbeatable deals on other big data plans - that makes them a natural choice of many a data hungry smartphone addict. But it's a bit shy on the free promotions stuff, and 4G coverage isn't as strong as the other networks.

BT SIM only deals

That familiar old stalwart of telecommunications BT is so-so when it comes to SIM only tariff prices. That's unless you're already a BT broadband customer, in which case you get some really favourable prices - a fiver less than the rest of the hoi polloi. Plus you get a BT Reward Card that can be spent anywhere that accepts Mastercard, the value of which depends on how much data you're in for.

Check below to see the current prices plans and what value Reward Card you can claim when you sign up. It's also worth noting that the 8GB and 20GB SIM only deals with BT also include free access to BT Sport on mobile.

For existing BT Broadband customers
(click the customer option at the top if the prices are more expensive)

iD SIM only deals

iD is a good option if bargain basement prices are what you covet most. This is a network run and owned by Carphone Warehouse - it piggybacks on the Three network. It's an excellent option if you want great value on a rolling monthly contract.

giffgaff SIM only deals

GiffGaff is very hard to beat on price – if you want to grab a cheap SIM card deal, this could be your best option. You can't argue with £5 a month. The cheap deals don't give you much of an allowance to play with, but if you just want to keep your phone going and available to use for calls and texts with the occasional bit of internet use outside of your home WiFi, GiffGaff is a strong offering. Look out for the T&Cs though as some of the big data deals throttle the speed after a few gig.

Virgin Mobile SIM only deals

Virgin Mobile has been going for a long time, and some of its SIM only deals are particularly attractive. They're all one-month rolling contracts, so you can stop paying at any time if you so wish, giving you flexibility if you want to change your plan or go for a phone-inclusive deal down the line. Prices start from as little as £9 a month.

Tesco Mobile SIM only deals

The UK's biggest supermarket has been known to offer competetive - if not stellar - SIM only deals, with low data prices starting around the £6 a month mark. Where it get's really interesting is if you download the Xtras app to an Android phone: you'll save £3 on your monthly bill, but you will have to see adverts every time you unlock your handset.

TalkTalk SIM only deals

TalkTalk is a telecoms company that also offers home phone, broadband and TV packages, so the best deals can be had if you sign up for more than one service. However, at the time of writing the cheapest deal is £3.95 per month for an admittedly measly 250MB of data. Better yet, for just £7.75 you can get 2.1GB.

Plusnet SIM only deals

Plusnet might be more well known for its broadband deals, but it's also keen to push some very cheap 30-day SIM only deals. You don't have to be a Plusnet customer, although you could get double the data on some of these SIM only deals if you are. You don't have to worry about signal either as Plusnet uses EE's network that covers 99% of the UK. Plusnet's latest cheap SIM only deals start at just £4 a month, check them out via the link below.

Freedom Pop SIM only deals

Freedom Pop is trying something new - offering contracts for FREE. The catch being that you only pay if you do over the allowances of your bundle or opt for a larger deal. The prices for doing so vary, so be sure to take a look at the small print. It seems that they feature a different offer each week, but seeing as you can cancel at any time, they may be worth a look.

Mobiles.co.uk SIM only deals

It's always worth checking out Mobiles.co.uk before settling on your SIM - its aggressive price cuts are often unmatched by anyone else. While the online retailer is known more for its handset contracts, it also offers a wide range of SIM only deals from all your favourite networks.

Carphone Warehouse SIM only deals

Carphone Warehouse doesn't just sell handset contracts. It also has a wide range of SIM only deals for Vodafone, O2, EE and ID. The online store is also known to include additional incentives such as half price fees for six months, free Beats by Dre headphones or Currys vouchers.

Which networks have coverage in my area?

It's one of life's (many) little frustrations - you sign up with a network, get your SIM up and running and then discover that you get no coverage at all in your house. Well this little pain in the neck can be avoided by using the dedicated coverage checker that most networks provide. Enter your postcode and you'll see whether your address has 2G (calls, texts and email), 3G (the basics plus picture messaging and faster web browsing) and 4G (all the powers of 3G, plus faster downloads, online gaming and media streaming) coverage.

We've provided links below to all the available coverage checkers on multiple networks. We'd advise not only checking coverage in your home, but also work, school, uni, favourite pubs and so on. Anywhere where you spend time on a regular basis really.

How does TechRadar make money from SIM only deals?

If you buy a phone after visiting this page, TechRadar will be paid a small commission by the network or reseller you buy from. This money is paid by the site you buy from and thus does not affect the amount you pay for your phone contract. If you go direct to the site you buy from, you would pay the same amount.

While some sites out there will be paid larger fees for pushing people to specific deals that aren't necessarily the cheapest, TechRadar will always find you the absolute best value. Trust and integrity is important to us, so if you ever think we're not displaying the very best deals let us know.

The SIM only deals on this page are checked every day to make sure they're still available and up to date! If you're ready to go SIM only, then head back to the top of this page and use our tool to find the perfect plan...